Magnetic skyrmions: advances in physics and potential applications

Dzyaloshinskii, I. A thermodynamic theory of ‘weak’ ferromagnetism of antiferromagnetics. J. Phys. Chem. Solids 4, 241–255 (1958).

Moriya, T. Anisotropic superexchange interaction and weak ferromagnetism. Phys. Rev. 120, 91–98 (1960).

Bogdanov, A. N. & Röβler, U. K. Chiral symmetry breaking in magnetic thin films and multilayers. Phys. Rev. Lett. 87, 037203 (2001). First theoretical prediction and description of magnetic skyrmions in thin films.

Röβler, U. K., Bogdanov, A. N. & Pfleiderer, C. Spontaneous skyrmion ground states in magnetic materials. Nature 442, 797–801 (2006).

Fert, A., Cros, V. & Sampaio, J. Skyrmions on the track. Nat. Nanotechnol. 8, 152–156 (2013).

Nagaosa, N. & Tokura, Y. Topological properties and dynamics of magnetic skyrmions. Nat. Nanotechnol. 8, 899–911 (2013).

Rohart, S., Miltat, J. & Thiaville, A. Path to collapse for an isolated Néel skyrmion. Phys. Rev. B 93, 214412 (2016).

Mühlbauer, S. et al. Skyrmion lattice in a chiral magnet. Science 323, 915–919 (2009).

Yu, X.-Z. et al. Real-space observation of a two-dimensional skyrmion crystal. Nature 465, 901–904 (2010).

Heinze, S. et al. Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions. Nat. Phys. 7, 713–718 (2011). First observation of skyrmions in thin magnetic films.

Romming, N. et al. Writing and deleting single magnetic skyrmions. Science 341, 636–639 (2013).

Yang, H., Thiaville, A., Rohart, S., Fert, A. & Chshiev, M. Anatomy of Dzyaloshinskii–Moriya interaction at Co/Pt interfaces. Phys. Rev. Lett. 115, 267210 (2015).

Fert, A. & Levy, P. M. Role of anisotropic exchange interactions in determining the properties of spin-glasses. Phys. Rev. Lett. 44, 1538–1541 (1980).

Fert, A. Magnetic and transport properties of metallic multilayers. Mater. Sci. Forum 59–60, 439–480 (1990).

Kubetzka, A., Bode, M., Pietzch, O. & Wiesendanger, R. Spin-polarized scanning tunneling microscope with antiferromagnetic probe tips. Phys. Rev. Lett. 88, 057201 (2002).

Bode, M. et al. Chiral magnetic order at surfaces driven by inversion asymmetry. Nature 447, 190–193 (2007).

Heide, M., Bihlmayer, G. & Blügel, S. Dzyaloshinskii–Moriya interaction accounting for the orientation of magnetic domains in ultrathin films: Fe/W(110). Phys. Rev. B 78, 140403 (2008).

Dupé, B., Hoffmann, M., Paillard, C. & Heinze, S. Tailoring magnetic skyrmions in ultra-thin transition metal films. Nat. Commun. 5, 4030 (2014).

Belabbes, A., Bihlmayer, G., Bechstedt, F., Blügel, S. & Manchon, A. Hund's rule-driven Dzyaloshinskii–Moriya interaction at 3d–5d interfaces. Phys. Rev. Lett. 117, 247202 (2016).

Boulle, O. et al. Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures. Nat. Nanotechnol. 11, 449–454 (2016).

Yang, H. Boulle, O., Cros, V., Fert, A. & Chshiev, M. Controlling Dzyaloshinskii–Moriya interaction via chirality dependent layer stacking, insulator capping and electric field. Preprint at arXivhttps://arxiv.org/abs/1603.01847 (2016).

Belabbes, A. et al. Oxygen-enabled control of Dzyaloshinskii–Moriya interaction in ultra-thin magnetic films. Sci. Rep. 6, 24634 (2016).

Di, K. et al. Direct observation of the Dzyaloshinskii–Moriya interaction in a Pt/Co/Ni film. Phys. Rev. Lett. 114, 047201 (2015).

Belmeguenai, M. et al. Interfacial Dzyaloshinskii–Moriya interaction in perpendicularly magnetized Pt/Co/AlOx ultrathin films measured by Brillouin light spectroscopy. Phys. Rev. B 91, 180405 (2015).

Nembach, H. T., Shaw, J. M., Weiler, M., Jué, E. & Silva, T. J. Linear relation between Heisenberg exchange and interfacial Dzyaloshinskii–Moriya interaction in metal films. Nat. Phys. 11, 825–829 (2015).

Hrabec, A. et al. Measuring and tailoring the Dzyaloshinskii–Moriya interaction in perpendicularly magnetized thin films. Phys. Rev. B 90, 020402(R) (2014).

Lavrijsen, M. et al. Asymmetric magnetic bubble expansion under in-plane field in Pt/Co/Pt: effect of interface engineering. Phys. Rev. B 91, 104414 (2015).

Pizzini, S. et al. Chirality-induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures. Phys. Rev. Lett. 113, 047203 (2014).

Soucaille, R. et al. Probing the Dzyaloshinskii–Moriya interaction in CoFeB ultrathin films using domain wall creep and Brillouin light spectroscopy. Phys. Rev. B 94, 104431 (2016).

Cho, J. et al. Thickness dependence of the interfacial broken systems. Nat. Commun. 6, 7635 (2015).

Moreau-Luchaire, C. et al. Additive interfacial chiral interaction in multilayers for stabilization of small individual skyrmions at room temperature. Nat. Nanotechnol. 11, 444–448 (2016).

Soumyanarayanan, A. et al. Tunable room temperature magnetic skyrmions in Ir/Fe/Co/Pt multilayers. Preprint at arXivhttps://arxiv.org/abs/1606.06034 (2016).

Woo, S. et al. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets. Nat. Mater. 15, 501–506 (2016).

Yu, G. et al. Room-temperature creation and spin–orbit torque manipulation of skyrmions in thin films with engineered asymmetry. Nano Lett. 16, 1981–1988 (2016).

Legrand, W. et al. Room-temperature current-induced generation and motion of sub-100 nm skyrmions. Nano Lett. 17, 2703–2712 (2017).

Jiang, W. et al. Blowing magnetic skyrmion bubbles. Science 349, 283–286 (2015). First report on the creation of skyrmions (skyrmionic bubbles) by current.

Chen, G., Mascaraque, A., N’Diaye, A. T. & Schmid, A. K. Room temperature skyrmion ground state stabilized through interlayer exchange coupling. Appl. Phys. Lett. 106, 242404 (2015).

Gilbert, D. A. et al. Realization of ground-state artificial skyrmion lattices at room temperature. Nat. Commun. 6, 8462 (2015).

Nandy, A. K., Kiselev, N. & Blügel, S. Interlayer exchange coupling: a general scheme turning chiral magnets into magnetic multilayers carrying atomic-scale skyrmions. Phys. Rev. Lett. 116, 177202 (2016).

Jonietz, F. et al. Spin transfer torques in MnSi at ultralow current densities. Science 330, 1648–1651 (2010). First demonstration of the interaction between skyrmions and currents.

Yu, X. Z. et al. Skyrmion flow near room temperature in an ultralow current density. Nat. Commun. 3, 988 (2012).

Sampaio, J., Cros, V., Rohart, S., Thiaville, A. & Fert, A. Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. Nat. Nanotechnol. 8, 839–844 (2013).

Iwasaki, J., Mochizuki, M. & Nagaosa, N. Current-induced skyrmion dynamics in constricted geometries. Nat. Nanotechnol. 8, 742–747 (2013).

Schulz, T. et al. Emergent electrodynamics of skyrmions in a chiral magnet. Nat. Phys. 8, 301–304 (2012).

Evenschor-Sitte, K., Garst, M., Duine, R. A. & Rosch, A. Current-induced rotational torques in the skyrmion lattice phase of chiral magnets. Phys. Rev. B 84, 064401 (2011).

Thiele, A. Steady-state motion of magnetic domains. Phys. Rev. Lett. 30, 230–233 (1973).

Tomasello, R. et al. A strategy for the design of skyrmion racetrack memories. Sci. Rep. 4, 6784 (2014).

Jiang, W. et al. Direct observation of the skyrmion Hall effect. Nat. Phys. 13, 162–169 (2016).

Hrabec, A. et al. Current-induced skyrmion generation and dynamics in symmetric bilayers. Preprint at arXivhttps://arxiv.org/abs/1611.00647 (2016).

Iwasaki, J., Mochizuki, M. & Nagaosa, N. Universal current–velocity relation of skyrmion motion in chiral magnets. Nat. Commun. 4, 1463 (2013).

Litzius, K. et al. Skyrmion Hall effect revealed by direct time-resolved X-ray microscopy. Nat. Phys. 13, 170–175 (2017).

Reichhardt, C. & Olson Reichhardt, C. J. Noise fluctuations and drive dependence of the skyrmion Hall effect in disordered systems. New J. Phys. 18, 095005 (2016).

Schütte, C., Iwasaki, J., Rosch, A. & Nagaosa, N. Inertia, diffusion, and dynamics of a driven skyrmion. Phys. Rev. B 90, 174434 (2014).

Zhang, X., Zhou, Y. & Ezawa, M. Antiferromagnetic skyrmion: stability, creation and manipulation. Sci. Rep. 6, 24795 (2016).

Jin, C., Song, C., Wang, J. & Liu, Q. Dynamics of antiferromagntic skyrmion driven by spin Hall effect. Appl. Phys. Lett. 109, 182404 (2016).

Barker, J. & Tretiakov, O. A. Static and dynamical properties of antiferromagnetic skyrmions in the presence of applied current and temperature. Phys. Rev. Lett, 116, 147203 (2016).

Kong, L. & Zang, J. Dynamics of an insulating skyrmion under a temperature gradient. Phys. Rev. Lett. 111, 067203 (2013).

Mochizuki, M. et al. Thermally driven ratchet motion of a skyrmion microcrystal and topological magnon Hall effect. Nat. Mater. 13, 241–246 (2014).

Thiaville, A., Rohart, S., Jué, E., Cros, V. & Fert, A. Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films. Europhys. Lett. 100, 57002 (2012).

Khvalkovskiy, A. et al. Matching domain-wall configuration and spin–orbit torques for efficient domain-wall motion. Phys. Rev. B 87, 020402(R) (2013).

Emori, S., Bauer, U., Ahn, S.-M., Martinez, E. & Beach, G. S. D. Current-driven dynamics of chiral ferromagnetic domain walls. Nat. Mater. 12, 611–616 (2013).

Ryu, K.-S., Thomas, L., Yang, S.-H. & Parkin, S. Chiral spin torque at magnetic domain walls. Nat. Nanotechnol. 8, 527–533 (2013).

Heinonen, O., Jiang, W., Somaily, H., te Velthuis, S. G. E. & Hoffmann, A. Generation of magnetic skyrmion bubbles by inhomogeneous spin Hall currents. Phys. Rev. B 93, 094407 (2016).

Yu, G. et al. Room-temperature skyrmion shift device for memory application. Nano Lett. 17, 261–268 (2016).

Zhou, Y. & Ezawa, M. A reversible conversion between a skyrmion and a domain-wall pair in a junction geometry. Nat. Commun. 5, 8 (2014).

Finazzi, M. et al. Laser-induced magnetic nanostructures with tunable topological properties. Phys. Rev. Lett. 110, 177205 (2013).

Hsu, P.-J. et al. Electric-field-driven switching of individual magnetic skyrmions. Nat. Nanotechnol. 12, 123–126 (2017).

Crum, D. M. et al. Perpendicular reading of single confined magnetic skyrmions. Nat. Commun. 6, 8541 (2015).

Hanneken, C. et al. Electrical detection of magnetic skyrmions by tunnelling non-collinear magnetoresistance. Nat. Nanotechnol. 10, 1039–1042 (2015).

Nagaosa, N., Sinova, J., Onoda, S., MacDonald, A. H. & Ong, N. P. Anomalous Hall effect. Rev. Mod. Phys. 82, 1539 (2010).

Hamamoto, K., Ezawa, E. & Nagaosa, N. Purely electrical detection of a skyrmion in constricted geometry. Appl. Phys. Lett. 108, 112401 (2016).

Lee, M. et al. Unusual Hall effect anomaly in MnSi under pressure. Phys. Rev. Lett. 102, 186601 (2009).

Neubauer, A. et al. Topological Hall effect in the A phase of MnSi. Phys. Rev. Lett. 102, 186602 (2009).

Kanazawa, N. et al. Discretized topological Hall effect emerging from skyrmions in constricted geometry. Phys. Rev. B 91, 041122(R) (2015).

Wang, K., Huang, Y., Zhang, X. & Zhao, W. Skyrmion-electronics: an overview and outlook. Proc. IEEE 140, 2040 (2016).

Parkin, S. & Yang, S.-H. Memory on the racetrack. Nat. Nanotechnol. 10, 195–198 (2015).

Kang, W. et al. Voltage controlled magnetic skyrmion motion for racetrack memory. Sci. Rep. 6, 23164 (2016).

Koshibae, W. et al. Memory functions for magnetic skyrmions. Jpn. J. Appl. Phys. 54, 053001 (2015).

Zhang, X. et al. Skyrmion–skyrmion and skyrmion–edge repulsions in skyrmion-based racetrack memory. Sci. Rep. 5, 7643 (2015).

Zhang, X., Zhou, Y., Ezawa, M., Zhao, G. P. & Zhao, W. Magnetic skyrmion transistor: skyrmion motion in a voltage-gated nanotrack. Sci. Rep. 5, 11369 (2015).

Zhang, X., Ezawa, M. & Zhou, Y. Magnetic skyrmion logic gates: conversion, duplication and merging of skyrmions. Sci. Rep. 5, 9400 (2015).

Schott, M. et al. The skyrmion switch: turning magnetic skyrmion bubbles on and off with an electric switch. Nano Lett. 17, 3006–3012 (2017).

Ma, F., Zhou, Y., Braun, H. B. & Lew, W. S. Skyrmion-based dynamic magnonic crystal. Nano Lett. 15, 4029–4036 (2015).

Roldan-Molina, A., Nunez, A. S. & Fernández-Rossier, J. Topological spin waves in the atomic-scale magnetic skyrmion crystal. New J. Phys. 18, 045015 (2016).

Kim, J.-V. et al. Breathing modes of confined skyrmions in ultrathin magnetic dots. Phys. Rev. B 90, 064410 (2014).

Carpentieri, M. et al. Topological, non-topological and instanton droplets driven by spin-transfer torque in materials with perpendicular magnetic anisotropy and Dzyaloshinskii–Moriya interaction. Sci. Rep. 5, 16184 (2015).

Finocchio, G. et al. Skyrmion based microwave detectors and harvesting. Appl. Phys. Lett. 107, 262401 (2015).

Garcia-Sanchez, F., Reyren, N., Sampaio, J., Cros, V. & Kim, J.-V. A skyrmion-based spin-torque nano-oscillator. New J. Phys. 18, 075011 (2016).

Huang, Y. et al. Magnetic skyrmion-based synaptic devices. Nanotechnology 28, 08LT02 (2017).

Pinna, D. et al. Skyrmion gas manipulation for probabilistic computing. Preprint at arXivhttps://arxiv.org/abs/1701.07750 (2017).

Rohart, S. & Thiaville, A. Skyrmion confinement in ultrathin film nanostructures in the presence of Dzyaloshinskii–Moriya interaction. Phys. Rev. B 88, 184422 (2013).

Siemens, A., Zhang, Y., Hagemeister, J., Vedmedenko, E. Y. & Wiesendanger, R. Minimal radius of magnetic skyrmions: statics and dynamics. New J. Phys. 18, 045021 (2016).

Kiselev, N. S., Bogdanov, A. N., Schäfer, R. & Rossler, U. K. Chiral skyrmions in thin magnetic films: new objects for magnetic storage technologies? J. Phys. D 44, 392001 (2011).

Everschor, K. Current-Induced Dynamics of Chiral Magnetic Structures: Skyrmions, Emergent Electrodynamics and Spin-Transfer Torques. Thesis, Univ. zu Köln (2012).

Wiesendanger, R. Nanoscale magnetic skyrmions in metallic films and multilayers: a new twist for spintronics. Nat. Rev. Mater. 1, 16044 (2016).

Romming, N., Kubetzka, A., Hanneken, C., von Bergmann, K. & Wiesendanger, R. Field-dependent size and shape of single magnetic skyrmions. Phys. Rev. Lett. 114, 177203 (2015).